NAMSW (NewAmsterdam Pharma Company N.V. Warrant)
Insider Trading Activity
Every open-market purchase and sale reported by NAMSW officers, directors and 10%+ beneficial owners on SEC Form 4, which must be filed within two business days of the transaction. Sales often reflect scheduled 10b5-1 plans or tax withholding rather than a directional view, so read counts alongside the size and the filer.
Market data may be delayed, incomplete, or inaccurate. Not a recommendation to buy, sell, or hold any security. Verify quotes with your broker before trading. See Terms §17.
| Filed | Insider | Role | Type | Shares | Value |
|---|---|---|---|---|---|
| 2026-05-27 | Louise Frederika Kooij | Chief Accounting Officer | MIXED | — | — |
| 2026-03-12 | LOUIS G LANGE | Director | Sell | — | — |
| 2026-03-10 | LOUIS G LANGE | Director | MIXED | — | — |
| 2026-03-09 | Johannes Jacob Pieter Kastelein | Chief Scientific Officer | MIXED | — | — |
| 2026-03-02 | Michael H. Davidson | Chief Executive Officer | MIXED | — | — |
| 2026-02-26 | Michael H. Davidson | Chief Executive Officer | MIXED | — | — |
| 2026-02-24 | Johannes Jacob Pieter Kastelein | Chief Scientific Officer | Sell | — | — |
| 2026-01-29 | Louise Frederika Kooij | Chief Accounting Officer | MIXED | — | — |
| 2026-01-27 | Louise Frederika Kooij | Chief Accounting Officer | MIXED | — | — |
| 2026-01-22 | Mayur Ian Somaiya | Chief Financial Officer | MIXED | — | — |
| 2026-01-09 | LOUIS G LANGE | Director | A | — | — |
| 2026-01-09 | William Lewis | Director | A | — | — |
| 2026-01-09 | Adele M. Gulfo | Director | A | — | — |
| 2026-01-09 | Kamp Hilde Johanna van der | Director | A | — | — |
| 2026-01-09 | John W Smither | Director | A | — | — |
| 2026-01-09 | Michael H. Davidson | Chief Executive Officer | MIXED | — | — |
| 2026-01-09 | Mark C. McKenna | Director | A | — | — |
| 2026-01-07 | Louise Frederika Kooij | Chief Accounting Officer | MIXED | — | — |
| 2026-01-07 | Mayur Ian Somaiya | Chief Financial Officer | MIXED | — | — |
| 2026-01-07 | Johannes Jacob Pieter Kastelein | Chief Scientific Officer | MIXED | — | — |
| 2025-12-29 | Louise Frederika Kooij | Chief Accounting Officer | MIXED | — | — |
| 2025-09-17 | James N Topper | Director | Buy | — | — |
| 2025-09-10 | Louise Frederika Kooij | Chief Accounting Officer | MIXED | — | — |
| 2025-09-10 | James N Topper | Director | Buy | — | — |
| 2025-09-05 | Louise Frederika Kooij | Chief Accounting Officer | Sell | — | — |
| 2025-09-04 | Louise Frederika Kooij | Chief Accounting Officer | M | — | — |
| 2025-08-27 | Louise Frederika Kooij | Chief Accounting Officer | Sell | — | — |
| 2025-08-25 | Johannes Jacob Pieter Kastelein | Chief Scientific Officer | Sell | — | — |
| 2025-08-13 | James N Topper | Director | Buy | — | — |
| 2025-07-17 | Douglas F Kling | Chief Operating Officer | MIXED | — | — |
| 2025-06-26 | James N Topper | Director | Buy | — | — |
| 2025-06-18 | James N Topper | Director | Buy | — | — |
| 2025-06-18 | Douglas F Kling | Chief Operating Officer | MIXED | — | — |
| 2025-06-03 | LOUIS G LANGE | Director | M | — | — |
| 2025-06-03 | Michael F Marino III | See Remarks | A | — | — |
| 2025-05-19 | Douglas F Kling | Chief Operating Officer | MIXED | — | — |
| 2025-05-02 | Juliette Berangere Audet | See Remarks | A | — | — |
| 2025-05-02 | LOUIS G LANGE | Director | M | — | — |
| 2025-04-21 | LOUIS G LANGE | Director | M | — | — |
| 2025-04-17 | Douglas F Kling | Chief Operating Officer | MIXED | — | — |
| 2025-04-17 | Adele M. Gulfo | Director | A | — | — |
| 2025-03-28 | LOUIS G LANGE | Director | M | — | — |
| 2025-03-28 | James N Topper | Director | Buy | — | — |
| 2025-03-28 | Douglas F Kling | Chief Operating Officer | MIXED | — | — |
| 2025-03-28 | Johannes Jacob Pieter Kastelein | Chief Scientific Officer | MIXED | — | — |
| 2025-03-28 | Michael H. Davidson | Chief Executive Officer | MIXED | — | — |
| 2025-03-28 | Louise Frederika Kooij | Chief Accounting Officer | M | — | — |
| 2025-03-26 | Johannes Jacob Pieter Kastelein | Chief Scientific Officer | M | — | — |
| 2025-03-19 | Douglas F Kling | Chief Operating Officer | MIXED | — | — |
| 2025-03-06 | James N Topper | Director | Buy | — | — |
| Insider | Role | Shares Held | Value |
|---|---|---|---|
| — | 10%+ Owner | 11,778,760 | — |
| — | 10%+ Owner | 11,339,949 | — |
| — | 10%+ Owner | 10,760,928 | — |
| — | 10%+ Owner | 10,686,018 | — |
| — | 10%+ Owner | 10,656,172 | — |
| — | Director | 3,801,000 | — |
| — | Chief Executive Officer | 459,859 | — |
| — | Chief Scientific Officer | 153,591 | — |
| — | Chief Financial Officer | 58,382 | — |
| — | See Remarks | 55,000 | — |
| — | Chief Operating Officer | 47,544 | — |
| — | Chief Commercial Officer | 43,000 | — |
| — | Chief Accounting Officer | 24,353 | — |
| — | See Remarks | 15,104 | — |
| — | Director | 14,260 | — |
| — | Director | 10,360 | — |
| — | Director | 10,360 | — |
| — | Director | 10,360 | — |
| — | Director | 10,360 | — |
| — | Director | 10,360 | — |
Form 4 reports a change in beneficial ownership by an officer, director or 10%+ holder, and must be filed within two business days of the transaction — so this is close to real time, unlike the 45-day-lagged 13F institutional data.
Transaction codes matter more than the raw buy/sell count. Code P is an open-market purchase — an insider choosing to buy with their own money, which is the signal most research treats as informative. Code S is a sale, but sales are frequently pre-scheduled under a 10b5-1 plan or cover tax withholding on vesting equity, so a run of sales often says nothing directional. Codes A and M are grants and option exercises rather than open-market decisions.
Full filing history and per-insider positions are on the NAMSW quote page; the site-wide leaderboard is on the insider transactions hub.